The invention relates generally to a tape for semiconductor package used to attach a chip and a lead frame or a chip and a substrate, method of manufacturing the same, and method of manufacturing the package using the tape, and more particularly to, a tape for semiconductor package, method of manufacturing the same, and method of manufacturing the package using the tape, in which a tape for semiconductor package of a sheet type or a roll type is formed in which a thermoplastic pattern matching to the lead frame or the portion to which the chip of the substrate is bonded, is provided, thus, reducing the cost and improving the productivity.
Generally, the semiconductor package includes various types of packages, such as the package in which chips are bonded to the lead frames like the package of lead on chip (LOC) type, the package in which chips are bonded to the substrate like a chip scale package (CSP), for example, a micro ball grid array (xcexcBGA) package, etc. Recently, as electronic devices become miniaturized and thinner, it is required that the package also be miniaturized and thinner. Specially, in order to enhance the competitiveness between the manufacturing companies, it is required that the productivity be improved and the cost be reduced. As one way of improve the productivity and reduce the cost, a method of simplifying the process of manufacturing the package, has been proposed.
FIG. 1 is a sectional view of a conventional lead on chip type for attaching a chip to a lead frame. The lead on chip package 10 includes a chip 11, a lead frame 12, an attachment layer 13 for attaching the chip 11 and the lead frame 12, a wire 14 for electrically connecting the chip 11 and the lead frame 12, and a protective layer 15 for protecting the chip 11 and the wire 14 from outside various damage.
FIG. 2 is a sectional view of a conventional chip scale package for attaching a chip to a substrate. The chip scale package 20 includes a chip 21, a substrate 22, an attachment layer 23 for attaching the chip 21 and the substrate 22, a lead 24 for electrically connecting the chip 21 and the substrate 22, a protective layer 25 for protecting the chip 21 and the lead 24 from outside various damage, and a solder ball 26 formed below the substrate 22.
The basic manufacturing process of the lead on chip type package 10 and the chip scale package 20 sequentially includes a wafer dicing saw process of individually separating the chips 11, 21 from the wafer, a chip attachment process of attaching the chips 11, 21 to the lead frame 12 or the substrate 22, a wire/lead attachment process of electrically connecting the chips 11, 21 and the lead frame 12 or the substrate 22, a molding and sealing process of protecting the chips 11, 21 from various damage factors, thus completing a assembly process.
After the assembly process, the package of lead on chip type 10 is manufactured by sequentially performing a mechanical/chemical deflash process, a tin plating process, a trim process, a form/singulation process, a pretest process, a burn-in test process, a post test process, etc., so that individual devices can be separated from the lead frame strip consisted of lead frame units and their lead shapes can be formed into a prescribed shape, thus functioning as a complete integrated circuit (IC), after the above assembly process.
The chip scale package 20 is pasted with a solder flux, after the above mentioned assembly process, and is manufactured by sequentially performing a solder ball attachment process, a reflow process and a singulation process.
Among the above mentioned package manufacturing process, the attachment layers 13, 23 used in the chip attachment process for attaching the chip 11 and the lead frame 12 or the chip 21 and the substrate 22 are formed of tape slices 31 made by cutting the tape 30 of a conventional three-layer structure shown in FIG. 3 into a constant size, using a cutting tool. The three-layer structure 30 is formed of films 32 and 34 made of adhesives at the top and bottom sides of the base film 33. Meanwhile, the elastomer is an adhesive mainly used in the chip scale package 20 and is formed with a nubbin type, etc. Generally, though a method of using the tape of three-layer structure is widely used in the chip attachment process, as mentioned above, in the chip scale package, a method of attaching the chip by which the tape of a three-layer structure is attached, a coating solution is dropped or a screen-printing is applied to cure it, and adhesive is dropped or a screen-printing is applied to cure it, is also used.
The process of attaching the chip 11 and the lead frame 12 in FIG. 1 will be now explained by reference to FIG. 4 using the tape slice 31.
FIG. 4 is a diagram for explaining the processes of attaching the chip 11 to the lead frame 12 of the lead frame strip 40 using a conventional tape slice 31. The lead frame strip 40 is consisted of a number of lead frame units 40A, 40B and 40C. The tape slice 31 in FIG. 3 is attached to the lead frame units 40A, 40B and 40C, respectively. Then, the chip 11 is raised to the tape slice 31 and the chip 11 and the lead frame 12 are attached by means of curing and press.
The process of attaching the chip 21 and the substrate in FIG. 2 is same to the principle of attaching process explained by reference to FIG. 4.
As explained above, in the package in which the chip is attached to the lead frame as in the package of lead on chip type and the package in which the chip is attached to the substrate as in the chip scale package, there are various types of methods to attach the chip and the lead frame or the chip and the substrate. When using the three-layer structure tape, there are problems that the cutting tool is necessarily required, the manufacture of the lead frame is difficult regarding to the cutting burr, the productivity is lowered and void is generated between the lead and the lead. In case of dropping a coating solution after the three-layer structure tape is attached or in case of dropping adhesive later after a screen-printing is applied to cure it, there are problems that not only a lot of time can be consumed but also it is difficult to drop adhesive at an exact position. Also, there are problems that it is difficult to control its height in case of using elastomer and it is difficult to remove void in case of a nubbin type. Therefore, the conventional chip attachment process consumes a lot of time, this causing lower of the productivity and thereby lower of throughput of the product due to above problems.
It is therefore an object of the present invention to provide a tape for semiconductor package, method of manufacturing the same and method of manufacturing the package using the tape, which can reduce the cost and improve the productivity, by providing a tape for semiconductor package of a sheet type or a roll type in which a thermoplastic pattern matching to the lead frame or the portion to which the chip of the substrate is attached.
In order to accomplish the above object, the tape for a semiconductor package is characterized in that it comprises a base film to side of which a release film is applied; a plurality of alignment holes formed at the edge of said base film; and a thermoplastic pattern formed on said release film so that it can match to a lead frame or the portion to which a chip of a substrate is attached.
Further, in order to accomplish the above object, the method of manufacturing a tape for a semiconductor package is characterized in that it comprises the steps of providing a base film; applying a release film at one side of said base film; forming, at a given distance, a plurality of alignment holes along the edge of said base film; and forming a thermoplastic pattern on said release film so that it can match to a lead frame or the portion to which a chip of a substrate is attached.
Also, in order to accomplish the above object, the method of manufacturing a semiconductor package is characterized in that it comprises positioning a tape for a semiconductor package in which a thermoplastic pattern is formed, at the top of a lead frame strip; attaching said thermoplastic pattern to a lead frame of said lead frame strip by means of press process, and then removing said tape; raising said chip over said thermoplastic pattern and then attaching said chip to said lead frame by means of curing and press process; performing a wire bonding process; performing a molding and sealing process to protect said chip; and performing a form and singulation process to separate individual devices.